Domestic heavy oil burner



May 10, 1938.

LINE

T. L. MAY 2,117,190

DOMESTIC HEAVY OIL BURNER Filed Sept. 14, 1936 3 Sheets-Sheet 1 Tia/77d;1.4/0;

,4ffornez May 10, 1938. T. L. MAY 2,117,190

DOMESTIC HEAVY OIL BURNER Filed Sept. 14, 1936 3 Sheets-Sheet 2 "STEANYMay 10, 1938. T. L. MAY 2,117,190

DOMESTIC HEAVY OIL BURNER Filed Sept. 14, 1936 3 Sheets-Sheet 3 //7van/0r Patented May 10, 1938 UNITED STATE PATENT- 0 FFICE 18 Claims.

My invention relates to fuel oil burning devices adapted for use indomestic service and more particularly to domestic fuel oil burningdevices especially designed to atomize and burn s residual oils commonlyknown as "heavy" fuel oils. Most oil burning devices, particularly thosedeveloped for domestic service, have heretofore been confined to the useof the distillate oils or "light" fuel oils, identified by the gradenumbers 1, 2 and 3 by the American Society for Testing Materials. Thedistillate oils are those oils which are distilled from crude petroleumat certain stages of the distillation proees, and each possesses'to agreater or less degree the common it of comparatively ready volatilityassists in the attainment of complete combustion and in producingasteady flame.

'lhere'sidualoilsontheotherhand,suchforexampleasthoseknownbygradenumbersijanddof the aforementioned American Society for Testing Materials have arelatively high viscosity at ordinary temperature and are substantiallynonvolatile. Owing to their thick, gummy nature at. ordinarytemperatures, flow of these oils through the conduits no ma y employedin fuel burning devices of the nature described is not readily attainedand satisfactory atomization of these oils employing the mechanicalcompressors and atomizing nozzles now in widespread use in domestic fueloil burning devices is almost impossible of attainment. However, it isknown that these residual oils possess highly combustible qualities andmoreover the cost thereof on the open market is substantially lower thanthat of the distillate oils. It is therefore an object of my inventionto provide a readily manufactured and economically operated domesticfuel oil burning device which is capable of producing a hot steady flameby the atomization and combustion of residual or heavy. oils.

It is further an object of my invention to pro: vide a fuel oil burningdevice which eliminates the need for a mechanical compressor in securingatomization of the oil and which consequently eliminates the employmentof moving parts. in accordance with my invention I employ a jet of steamfor atomizing the fuel oil at an atomizing nozzle and in order tomaintain a quantity of steam at suitable pressures, I provide anautomatically controlled steam generator having an independent heatingmeans other than the oil burner device, the steam output of the'generator being maintained'automatically within -fixed limits by meanscontrolling the generator heating means, and the water input, to thegenerator being contro led in accordance with the water level therein.ther, in accordance with my invention, I employ a portion of the heatdeveloped within the aforesaid steam generator for preheating the oilprior to its passage to the atom'izing nozzle to a relatively hightemperature and I control the rate of fiow' of the oil and steam to theatomizing nozzle manually in order to obtain a fixed definite ratiotherebetween and also I control the flow of oil and steam to the nozzleautomatically in accordance with the temperature of a medium heated bythe operation of the oil burning device.

My invention will be more fully understood from a consideration of thefollowing particular description of embodiments thereof, and of thedrawings attached thereto, and the features of my invention which Iconsider to be novel are pointed. out with particularity in the claimsap pended thereto.

. In the drawings:

Fig. l is a general view of an oil burning device of my invention,certain parts thereof being in section, and a control circuit beingincorporated therewith;

Fig. 2 is a plan view of the heater plates shown in section in Pig. 1,the upper plate being partially removed to illustrate a portion of thelower plate;

Hg. 3 is a sectional view of a preferred form of atomizing nozzle,showing the oil and steam passages therethroush; and

Fig. 4 is an illustration of an oil burning device employing alternativeforms of boiler, heating device, and water control.

In Fig. 1 the numeral l indicates an atomizing nomle which is moreclearly shown in Fig. 3. The numeral 2 indicates generally a steamgenerator to which is connected the steam conduit 3 and the inlet orwater'conduit l. The numeral I indicates generally a tank for thestorage of a residual or "heavy fuel oil the surface of which isrepresented at t. g

The steam generator comprises a water boiler formed of a cylindricalcasting 1 having the top and bottom members! and I secured thereto bymeans of the bolts I0 and II respectively. The top and bottom members 8and 9 are provided with suitable gaskets represented at I2 in order toassure a satisfactory water-tight seal between these members and thecylindrical casting I. The water boiler is mounted on an insulatingblock I3 preferably of porcelain having a recessed bottom providing aterminal box I4 and the porcelain block I3 is in turn supported on amounting base I5 adapted to rest on the floor or other support on whichthe oil burning device is mounted.

The heating element for the steam generator 2 is shown as a pair ofspaced plates l5 and I6, spaced apart in a vertical direction andmounted on the porcelain block H which is provided with a plurality ofupstanding knobs I8 on its upper The lower plate I6 is provided withsuitable apertures adapted to fit over the raised central portions I9 ofknobs I8 and permit the lower plate IE to be mounted on the knobs I8.The upper plate I5 rests on the top of the raised central portions I9 ofknobs I8 and is thereby spaced from the lower plate l6 at the edgesthereof. Lower plate I6 is secured by means of the bolts 20 brazed orotherwise secured to the lower surface thereof and extending downwardlythrough suitable apertures provided in the porcelain block I1, the lowerplate member 9 of the water boiler, and in the porcelain block I3. Theblock I1 is secured to block I3 by means of the bolt 2| extendingdownwardly through suitable apertures provided therein and in the lowermember 9 of the water boiler and the porcelain block I3.

" The bolt 2| is provided with an enlarged head having a central tappedaperture therein and a screw 22 extends through a suitable apertureprovided in the upper plate I5 and through .an enlarged apertureprovided in the lower plate I6 and into the tapped aperture in thecentre of the head of bolt 2|. Washers are provided between plate l5 andthe head of bolt 2| in order to properly space plate I5 from plate Ii atthe centre thereof. Bolts 20 and 2| extending intothe terminal box- I4provide a ready means for connectingthe heating elements I5 and I6 in anelectric circuit whichis completed through the water maintained in thesteam generator 2.

The generator 2 is provided with a steam outlet 26 to which is connectedthe conduit 3 extending to the atomizing nozzle I where the steamconduit 3 connects with steam passages provided within the nozzle (shownmore clearly in Fig. 3). A pressure operated switch 2'! of well knownconstruction is connected to conduit 3 and is adapted to open andcloselits contacts 21a and 21b in response to variations in steampressure within the generator 2 respectively above and belowpredetermined limits. A second pressure operated switch 23 is alsoconnected in the steam conduit 3 and is adapted to open and close itscontacts 280. and 28b in response to variations in. steam pressureingenerator. 2 respectively below and above a second pair .ofpredetermined limits. A solenoid operated valve 29, also of well knownconstruction, is connected in series in the steam conduit 3 and isarranged to be normally closed and to open only upon energization 01'its solenoid. A manually operated valve 30 is also connected in seriesin conduit 3 and permits a manual adjustment of the rate of flow ofsteam through the corfduit when the solenoid valve 29 is open.

The water inlet conduit 4 enters the water boiler through the elbowmember 3| at a point adjacent the bottom of the boiler and close totheheating elements I5 and I6. A bafile 32 isprovided in the interior ofthe water boiler in order to prevent splashing of the water directlyonto the heating elements I5 and I6, and the water conduit 4 is Wound ina plurality of coils 33 about the steam generator 2 and in good heattransfer relation with the exterior surface of the cylindrical member Iin order that the water entering the boiler may be preheated tofacilitate the more rapid generation of steam therein and to preventsevere fluctuations in steam pressure therein due to the entrance ofcold water. Connected in series with the water inlet pipe 4 are themanually operated valve 34 and the solenoid valve 35. The manuallyoperated valve 34 permits a manual adjustment of the rate of water flowthrough conduit 4, and the solenoid operated valve is arranged tonormally close the conduit 4 and to open only in response to theenergization'of its solenoid.

The oil supply tank 5 is arranged at a higher level than the nozzle Iand oil is conducted therefrom through an enlarged oil conduit 40,reducer 4|, and oil conduit 42 of reduced section. The oil conduit 42 iswound in a plurality of coils 43 which are supported on the exteriorgenerator 2 in good heat transfer contact therewith, and extends to theatomizing nozzle I, where it connects with the oil passages therein.Connected in series with the oil conduit 42 and adjacent the nozzle endthereof are the solenoid valves 44 and 45 and the manually operatedvalve 46. Each of the solenoid valves 44 and 45 are arranged to normallycompletely close conduit 42 and to open only upon energization of theirsolenoids. The manually controlled valve 46 permits a manual adjustmentof the rate of flow of oil in conduit 42 when the valves 44 and 45 areopen.

A T-connection 50 is made in the steam conduit 3 adjacent the steamgenerator 2, to which is connected a conduit 5| of relatively small sizewhich is led back through the reducer 4|, the enlarged oil conduit 40and up through the oil supply tank 5. The purpose of the conduit 5| isto preliminarily preheat in order to render more fluid the oil in theoil tank and enlarged oil conduit 40. The steam exhaust from the conduit5| may be employed for humidifying the atmosphere in an enclosed space,such for example as in a room of the house or other structure to beheated.

In order to assure the most eflicient operation of the generator 2 andto prevent the escape of heat from the oil conduit 42 and steam conduit3, these members are provided with an exterior heat lagging as indicatedat 5h Although this heat lagging is shown only around the generator andthe coils of conduits 42 and 4 adjacent thereto, it will be apparentthat it may be, and in some cases preferably is, extended around theconduits 42 and 3 up to the proximity of the nozzle I.

Steam is generated within the steam genera' surface of the cylindricalcasting 'I of steam H and 62 of the relay 63 and also the operatingsolenoid 64 of a relay 65 having the normally closed contacts 66. Relay63 is arranged to close its contacts 6| and 62 upon the energization ofits operating coil 61. The relay 65 is adapted to open its normallyclosed contacts 66 whenever current flows between the plates I5 and I6.

A control circuit for the solenoid valve 35 in the water pipe 4 isprovided including in series therewith the normally closed contacts 66of relay 65 and also the contacts 21a and 21b of the pressure switch 21.Thus the solenoid valve 35 is energized to open the water pipe 4whenever the contacts 66 of relay 65 are closed and the contacts 21a and21b of pressure switch 21 are also closed.

The contacts 21a and 21b of pressure switch 21 are also included inseries in the energizing circuit for relay 63. Thus the relay 63 closesits contacts 6| and 62 to supply heat to the generator 2 in response tothe closure of the contacts of pressure switch 21 and water is suppliedto the generator 2 whenever the water level within the generator fallsbelow the level of the upper plate I5 thus breaking the circuit betweenthe plates.

Pressure switch 21- is arranged to close its contacts 21a and 21bwhenever the steam pressure within the generator 2 falls below apredetermined lowllmit and to retain its contacts closed until thepressure reaches a predetermined upper limit. Thus the pressure switch21 operates to control the maintenance of the steam pressure within thegenerator 2 within predetermined limits and also to control theoperation of the solenoid valve 35 thereby to control the supply ofwater to the generator 2 in accordance with the water level therein.

In Fig. 3 I have illustrated one form of nozzle which may be employed inthe oil burner device of my invention. The nozzle as illustratedcomprises a casing I having therein a steam passage MI and an oilpassage I02. The nozzle is provided with a nozzle head I03 havingtherein a central oil passage I04 terminating in a restricted openingI05. Steam passages I06 communicating with the steam chamber I 01 arealso provided in nozzle head I03 and the restricted annular passage I06located adjacent the oil opening I communicates with the steam chamberI01. When steam under pressure is supplied to the nozzle passages IN ahigh velocity blast of steam escapes through the annular aperture I03and when an oil conduit is connected to the nozzle passage I 02 oildribbles through the oil opening I05 in nozzle head I03 and is caught upin the high velocity steam blast and thereby atomized and thoroughlymixed with the escaping steam. A long narrow blast of atomized oil andsteam is thus projected from the nozzle. If it is desired to provide afan shaped flame steam may be permitted to escape fromthe chamber I01through the drill holes I03 and peripheral passages IIO which direct thesteam in a cone having a greater angle than that escaping from theopening I08. The particular form of nozzle employed is not essential tomy invention, it being understood that any form of nozzle which gives asatisfactory atomization and mixing of the oil with the escaping steammay be used.

The blast of steam at high velocity through the annular passage I06, aswill be understood by those familiar with the art, tends to reduce thepressure at the oil opening I05. Thus oilis forced from the tank 5 notonly by gravity, as

indicated above, but also by the Venturi action of the high velocitysteam blast. In order to assure a combustible mixture of oil with thesteam in the blast from nozzle I, and to prevent severe variations inthe ratio of oil to'steam in the blast, it is necessary to maintain apressure head of oil at the nozzle at all times during operation. Thus,in the modification illustrated in Fig. 1, the level of the oil supplytank 5 with regard to the oil conduit and nozzle is arranged so that apressure head of oil is maintained at the nozzle at all times duringoperation.

The velocity of the steam blast issuing from the annular aperture I03 ofthe nozzle head is an important factor in obtaining satisfactoryatomization of the oil and in obtaining the proper type of flame foreflicient heating, and for any given type of nozzle this velocity is afunction of steam pressure generated within the generator 2. I havefound that, when employing a nozzle as illustrated in Fig. 3 and indomestic installations wherein the flow of oil ordinarily is about 1 to2 gallons per hour and does not exceed about gallons per hour duringoperation, a quiet, steady, efliciently heating flame is obtained whenthe steam pressure ranges between 5 and pounds per square inch.Preferably I adjust the settingof the pressure switch 21 to control thesteam pressures within the generator 2 between the limits of 8 and 11pounds.

Referring again to Fig. 1, a control circuit is also provided for thesolenoid valves 29, 44 and 45 in parallel with one another and also inparallel with the primary winding of the ignition transformer 15 and inseries with the contacts 16 and 11 of the thermal or other temperatureresponsive device 18 arranged to be responsive to temperature variationsin a medium to be heated by means of the oil burner in accordance withpractices well known in the art. The secondary winding of thetransformer 15 is connected to the ignition terminals 13 locatedadjacent the nozzle I and in the path of a blast of atomized oil andsteam from the nozzle. Thus when thermostat 10 closes its contacts 16and 11 the solenoid valves 29, 44 and 45 are simultaneously operated topermit the flow of high velocity steam and of oil through the nozzle Ithereby to secure a blast of atomized oil and steam therefrom. At thesame time the terminals 18 are energized thereby igniting the blast ofoil' and steam from the nozzle I. When the thermostatic device 10operates to open its contacts the flow of oil and steam to nozzle I isshut off by the solenoid valves 23, 44 and 45 due to the deenergizationof the solenoids thereof, and the terminals 19 are also deenergized. Thefunction of solenoid valve 44 is duplicated in valve 45 .for safetypurposes in order to minimize the danger due to failure of either onevalves.

The pressure switch 28 is arranged to be responsive to steam pressureswithin the generator 2, and its contacts a and 261) are connected inseries in the common energizing circuit for the of these solenoid valves23, 44 and 45 and ignition terminals 19, in order that, particularly instarting up the burner, generator 2 may be permitted to build up theproper steam pressure before the valve 23 in conduit 3 is opened. Thus,when pressure switch 21 is set to close its contacts at 8 pounds steampressure and to open its contacts at 11 pounds, I have found itsatisfactory to adjust pressure switch 28 to open its contacts at a lowlevel such'as 3 pounds and to close'its contacts at a levelapproximating the lower limit of pressure switch Zl-as for example, 8pounds;

Thus during starting, and at any time during operation, when steampressure within the generator is lower than, or falls to 3 pounds,pressure switch 28 operates to deenergize the valves 29, 44 and 45 andthus to. prevent the supply of steam at undesired low pressures and oilto the nozzle l. Furthermore during starting, the supply of steam tonozzle l is prevented until the steam pressure attains the lower limitof the desired range of pressures.

In describing the operation of the above described heavy fuel oil burnerdevice it will be' switch 2i completes the circuit for the energizingcoil Sl oi? relay 63 which may be traced. as follows: from. left handline terminal through conductors 80 and ti, contacts Ma and 21b ofpressure switch 2?, conductor 82, operating coil 6i of relay 63 to theneutral line conductor 83. Relay 63 thus operates to close its contactsEl and 62 thus closing the heating circuit to the heating plates l5 and86, which may be traced as follows; line conductor 8t, contacts ill ofrelay 83, conductor 84 to bolt 29 and lower plate 66, upper plate l5,bolt ll, conductor 85, contacts 62 of relay 63, conductor 8t, operatingcoil 66 of relay 65, conductor St to the right hand line terminal. Thiscircuit is broken between the plates it and it due to the absence ofwater within the generator 2 and thus the operating coil 6d of relaytill: is deenergized and the contacts 56 thereof are closed; The closureof contacts Zia and Z'lb oi pressure switch 2 l also completes a circuitfor the solenoid valve 35 in water pipe ,4 which includes in seriestherewith the normally closedcontacts 5d of relay 65. This circuitextends from the left hand line terminal, conductors 8d and Bi, contacts2M and ill) of pressure switch 2?, conductor 32, conductor d8, contacts6%, conductor 89, solenoid valve conductor 5m to the neutral lineconductor 33. Thus solenoid valve 35 is energized to open the water pipe4 and to supply water to the generator 2. When the water reaches thelevel of upper plate it the energizing circuit for plates iii and itabove traced is completed and the operating coil Gd of relay E55 isenergized, thus opening the contacts 68 and deenergizing the circuit forthe solenoid valve 35. Solenoid valve 35 therefore closes the pipe line4 to shut off the flow of water to the generator 2. Steam pressure nowbuilds up within the steam generator 2 and when it has reached apredetermined pressure limit as above de-= scribed, the contacts 28d and28b of pressure switch 28 close. Closure of these contacts completes theenergizing circuit for solenoid valves 29, 44 and 45 as follows: fromright hand line terminal through conductors Bl and iii, contacts'lfi'and ll of the thermostat l8, conductor 92, contacts 28a and 28b 01pressure switch 28 which are now closed, conductor 9e, conductor 95, thesolenoid of valve 29, conductor 96 to the neutral line conductor Thesolenoids of valves M and W are connected in shunt with the solenoid ofvalve 29 by means oi the conductors aiimoo mains deenergized when relay63 closes and thus ture of the oil in the conduit d2 should exceed, for

and 98. Theprimary winding of ignition transformer "i5 is also connectedin a series circuit with the contacts 16 and ll of thermostat l8 andwith the contacts 28a and 28b of pressure switch 28 by means of acircuit which is traced as follows: right hand line terminal throughconductor 8i, conductor 9|, contacts 16 and ll of thermostat l8,conductor 92, contactsof pressure switch 28, conductor 93, primarywinding of transformer 15, conductor 91 to neutral line conductor 83.Thus when the thermostat contacts l6 and ll and the contacts of pressureswitch 28 are closed a blast of atomized oil and steam is delivered fromthe nozzle l and is ignited by the ignition terminals l9 connected tothe secondary winding of transformer l5.

The pressure switch 2! maintains its contacts 21a and 21b closed untilthe steam pressure within generator 2 reaches a predetermined high limitas above described, when contacts 21a and 21b open. This deenerglzes thecoil 61 of relay t3 and opens the heating circuit for the plates I5 andM5 at the contacts 6! and 62 of relay 63. This also deenergizes the coil64 of relay 65 permitting the contacts 66 to close, but the circuit forsolenoid valve 35 is now open at the contacts 2M and 21b of pressureswitch 2'! so that this solenoid valve remains closed. When the steampressure within generator 2 again falls to the lower limit determined bythe lower setting of pressure switch 21 this switch again closes itscontacts to reenergize relay 63, to close the heating circuit for platesl5 and Hi. This cycle of operation continues until the water levelwithin the generator again falls below the upper plate l5 at which timeas above explained relay 65 rethe energizing circuit for the solenoidvalve 35 is again completed to supply more water to the generator 2.

If at any time during operation the pressure of steam within thegenerator 2 falls below the low limit determined by the lower setting ofpressure switch 28 this pressure switch again opens its contacts 28a and28b to deenergize or to prevent the energlzation of the solenoid valves2'9, 44 and 45 and also to deenergize or to prevent the energization ofthe transformer 15, until the steam pressure within generator 2 againbuilds up.

When the desired temperature is obtained in the medium heated by theoperation of the oil burner device the thermostatic device 18 as is wellunderstood opens its contacts to decnergize the transformer E5 and thesolenoid valves 29. L

M and 45 which then operate to close the steam and oil conduits 3 and 42respectively.

as has been pointed out above, the oil conduit 4'2, of reducedcross-section, is arranged in a plurality of coils 43, supported on, andin good heat transfer relation with, the exterior surface of thecylindrical casting l of steam generator 2. During the course of itsflow through the coils 43, the oil in the conduit 42 acquires arelatively high temperature approaching that of the steam within thegenerator 2. It has been found that the characteristics and behaviour ofthe flame at the nozzle i are dependent, particularly in starting, onthe temperature of the oil in conduit 42; too low a temperature causes agusty, intermittent or inefficient flame, and, if the temperature ismuch too low may prevent ignition altogether. It is my present belief,although I do not wish to be limited thereto, that the temperamostsatisfactory operation of the oil burner, a temperature of about 175 F.

In Fig. 4 I have illustrated an alternative form 'of steam generatoremploying a well known form of immersion unit as a heating element andfurther employing a pair of float valves for controlling the flow ofwater into the steam generator. The steam generator shown in Fig. 4comprises a casting I40 provided with an upper closure member'or plate III secured thereto by means of the screws H2 and having the gasket H3therebetween. The member I40 is provided with a steam outlet 26 to whichis connected the steam conduit 3 which is connected at its end to thenozzle I. A water inlet pipe 4 is also connected to a suitable openingprovided in the member I40 to deliver water interiorly oi the generator2. The

,Water inlet pipe is connected within the generator to the inlet of thefloat controlled valve II4 the outlet II5 of which is connected to theinlet of the second float control valve IIB. Each of the valves H4 andH0 is provided with a float illustrated respectively at H1 and H8 and aswill be obvious, each is adapted to control the flow of water into thegenerator in accordance with the level of the water contained therein.

The heating element II! for thegenerator 2 comprises a well known formof immersion heating unit mounted within the generator and adapted to beconnected to an electrical circuit through the terminal chamber I20.

The oil conduit 42 is wound in a plurality of coils 43 which are mountedon and securedto the exterior of the member I40 in good heat transferrelation therewith and one end of the conduit 42 is connected to thenozzle I in communication with the oil passages therein. Connected inseries with'the oil 'conduit are the solenoid valves 44 and 45 and themanually controlled valve 46. Connected in series with the steam conduit3 are the pressure switches 21 and having contacts 21a and 21b and 28aand 28!) respectively, the solenoid operated valve 29, and the manuallyoperable valve 30.

Because of the use of an immersion heater and also because of theemployment of the float controlled valves for controlling the flow ofwater into the generator the control circuit for the generator of Fig. 4is considerably simplified. The immersion heater is connected in seriesacross the power supply source through the contacts 210 and 21b of, thepressure switch 21. Thus the heat supplied to the generator 2 iscontrolled directly by the operation of the pressure switch 21 inresponse to steam pressure within the generator. The solenoid valves 29,44 and 45 and the ignition transformer 15 are controlled d rectly by thejoint operation of the thermostat device 10 and the pressure switch 28in the manner fully explained above in connection with Fig. l.

In describing the operation of the apparatus illustrated in Fig. 4 itwill be initially assumed that no water has been admitted to thegenerator 2, that the thermostatic device 18 has cosed its contacts 16and 11, and that the main switch 00.

has been closed. Under these circumstances the contacts 28a and 28b ofpressure-switch 20 are open and the contacts 21a and 21b of pressureswitch 21 are closed. Moreover each of the floats H1 and H8 aredepressed thereby opening the valves H4 and H6 to permit water to flowinto the steam generator 2. When the water has reached a desired levelvalves H4 and H6 operate to shut oi! the flow of water. Since pressureswitch 21 is closed current is supplied to the immersion heating elementI I0 to thereby evaporate the water in the generator 2 and to generatesteam pressure therein. Pressure switch 21 remains closed until adesired maximum pressure within the generator 2 is obtained at whichtime these contacts open to shut off the heating circuit. The contactsof pressure switch 28 remain open until thesteam pressure within thegenerator 2 reaches a desired level determined by the upper setting ofthe pressure switch 20 as described above, and when this point has beenreached contacts 28a and 28b close to energize a circuit for thesolenoids 20, 44 and 45 and for the ignition transformer 15. A blast ofatomized oil and steam is thus projected from the nozzle I and ignitedby means of the ignition terminals 19 and continues so long as thethermostat contacts 1G and 11 remain closed. When a desired temperatureof the medium to be heated by the oil burning device of my invention hasbeen attained contacts 15 and 11 of thermostat .18 open to therebydeenergize thevalves 29, 44 and 45 and to close the conduits 3 and 42.

While in accordance with the patent statutes I have described in detailan embodiment of my invention I do not wish to be limited thereto andaim in the appended claims to cover all such modifications of myinvention as may occur to those skilled in the art and which fall withinthe true scope of my invention.

What I claim as new and desire to secure by Letters Patent of the UnitedStates, is:

1. In a burner for non-volatile residual fuel oils of high viscosity atordinary temperatures, the combination of a nozzle, a steam generator, asteam conduit connecting said generator to said nozzle, and anindependent heating device associated with said generator, with anindependent means responsive to steam pressures within said generatorfor controlling the operation of said generator whereby to maintainwithin said generator steam pressures within predetermined upper andlower limits and to provide a substantially constant blast of steam atsaid nozzle during the operation of the burner, an oil conduit connectedto said nozzle, and means supplying oil to said conduit and maintaininga pressure head of oil at said nozzle, said oil conduit having a portionadjacent saill fuel oil supply adapted for the free flow of such oiltherethrough at ordinary temperatures and another portion arranged inintimate heat transfer relation with the steam within the generator,whereby the oil therein acquires a relatively high temperatureapproaching that of the steam.

2. In a burner for non-volatile residual fuel oils of high viscosity atordinary temperatures, the combination of a nozzle, a steam generator, asteam conduit connecting said generator to said nozzle, and anindependent heating device associated with said generator, with anindependent means responsive to steam pressures within said generatorfor controlling the operation of said generator whereby to maintainwithin said generator steam pressures within predetermined upper andlower limits and to provide a substantially constant blast of steam atsaid nozzle during the operation of the burner, an oil conduit connectedto said nozzle, and means supplying oil to said conduit and maintaininga pressure head of oil at said nozzle, a portion of said oil conduitadjacent said fuel oil supply being provided with means for maintaininga free flow of said oil and a steam conduit connecting said generator tosaid nozzle, with an oil conduit connected to said nozzle, and meanssupplying oil to said conduit and maintaining a pressure head of oil atsaid nozzle, said oil conduit having a portion adjacent said fuel oilsupply adapted for the free flow of such oil therethrough at ordinarytemperatures and another portion arranged in intimate heat transferrelation with the generator whereby the oil therein acquires arelatively high temperature approaching that of the steam.

ipln a burner for non-volatile residual fuel oils of high viscosity atordinary temperatures, the combination of a nozzle, a steam generator,and a steam conduit connecting said generator to said nozzle, with anoil conduit connected to said nozzle and means supplying oil to saidconduit and maintaining a pressure head of oil at said nozzle, a portionof said oil conduit adjacent saidr fuel oil supply being provided withmeans for maintaining the free flow of such oil therethrough and anotherportion arranged in intimate heat transfer relation with the generatorwhereby the oil therein acquires a relatively high temperatureapproaching that of the steam.

5. In a burner for non-volatile residual fuel oils of high viscosity atordinary temperatures, the combination of a nozzle, a steam generator,and a steam conduit connecting said generator to said nozzle, with anoil conduit connected to said nozzle, and means supplying oil to saidconduit and maintaining a pressure head of oil at said nozzle, said oilconduit having a portion adjacent said fuel oil supply adapted for thefree .fiow of such oil therethrough at ordinary said nozzle, said oilconduit having a portion of relatively large cross-section adjacent saidfuel oil supply adapted for the free flow of such oil therethrough andanother portion of relatively small cross-section and arranged inintimate heat transfer relation with the generator whereby the oiltherein acquires a relativelyhigh temperature approaching that of thesteam. v

7. In a fuel oil burner, the combination of a nozzle, means comprising asource of oil and an oil conduit for maintaining a pressure head of oilat said nozzle, a steam generator, a steam conduit connecting saidgenerator to said nozzle and an independent heating device associatedwith said generator, with an independent means responsive to steampressure within said generator for controlling the operation of saidindependent heating device to maintain steam pressures within saidgenerator within predetermined upper and lower limits and to provide asubstantially con-a stant blast of steam at said nozzle during theoperation of the burner, whereby a substantially constant ratio of steamto oil is maintained in the blast from the nozzle.

8. In a fuel oil burner, the combination of a nozzle, means comprising asource of oil and an oil conduit for maintaining a pressure head of oilat said nozzle, a steam generator, a steam conduit connecting saidgenerator to said nozzle; and an independent heating device associatedwith said generator, with an independent means responsive to steampressures within said genera tor for energizing and de-energizing saidindependent heating device to provide a substantially constant blast ofsteam at said nozzle during the operation of the burner, whereby asubstantially constant ratio of steam to oil is maintained in the blastfrom the nozzle.

9. In an automatic oil burner comprising a nozzle, means comprising asource of fuel oil sup ply and an oil conduit for maintaining a pressurehead of oil at said nozzle, a steam generator, a conduit connecting saidgenerator to said nozzle, an independent heating device associated withsaid generator, means responsive to steam pressures within saidgenerator for controlling the operation of said generator, and a waterconduit connecting said generator to a source of water supply, saidwater conduit having a portion coiled about the generator in intimateheat transfer relation therewith for preheating the water therein toprevent undesirable pressure fluctuations within the generator, wherebysubstantially constant predetermined steam pressures are maintainedwithin said generator and a substantially constant ratio of steam to oilis maintained in the blast from the nozzle during operation of theburner.

10. In an oil burner, the combination of a nozzle, an oil conduitconnecting said nozzle to a supply of fuel oil, a steam generator, asteam conduit connecting said nozzle to said steam generator, anindependent heating device for said generator, means responsive to steampressures within said generator for controlling the operation of saidheating device to maintain steam pressure within said generator withinpredetermined upper and lower limits, valves, in said oil and steamconduits, a thermal responsive device, and means responsive to theoperation of said thermal responsive device for actuating said valves toproduce a blast of atomized oil and steam from said nozzle.

11. In an oil burner, the combination of a nozzle, an oil conduitconnecting said nozzle to a source of fuel oil, a steam generator, aconduit connecting said nozzle'to said steam generator, an independentheating device for said generator, means responsive to steam pressureswithin said generator for controlling the operation of said heatingdevice to maintain steam pressures within said generator withinpredetermined upper and lower limits, 9. thermal responsive device,valves located in said oil conduit and said steam conduit, meansresponsive to the operation of said thermal responsive device foractuating said valves to control a blast of atomized oil and steam fromsaid nozzle, and means for controlling said latter mentioned means inaccordance with predetermined pressure conditions in the steamgenerator.

12. In anoil burner, the combination of a nozzle, an oil conduitconnecting said nozzle to a 4 source of fuel oil, a steam generator, anindependent heating device for said generator, means responsive to steampressures within said generator for controlling the operation 01' saidheating device to maintain steam pressures within said generator withinpredetermined upper and lower limits, a thermal responsive device.normally closed valves located in said oil and steam conduits, meansresponsive to the operation of said thermal responsive device foropening said valves to permit the discharge of a blast 0t atomizedvsteam and oil from said nozzle, and means for rendering inoperativesaid last mentioned means whenever the steam pressure within saidgenerator falls below a predetermined value.

13. In an oil burner, the combination of a nozzle, an oil conduitconnecting said nozzle to a source of fuel oil, a steam generator, aconduit connecting'said nozzle to said steam generator, an independentheating device for said generator, means responsive to steam pressureswithin said generator for controlling the operation of said heatingdevice to maintain said pressures within a predetermined limited range,a thermal responsive device, valves located in said oil conduit and saidsteam conduit, means responsive to the operation of said thermalresponsive device for actuating said valves to control a blast ofatomized oil and steam from said nozzle, and another means responsive tosteam pressures within said generator for rendering inoperative saidlast mentioned means when said steam pressure falls below a limit lowerthan said predetermined limited range and subsequently renderingoperative said last mentioned means only when steam pressure has risento said predetermined limited range.

THOMAS LESLIE MAY.

